How to fix warping

Warping occurs due to material shrinkage whilst 3D printing, which causes the corners of the print to lift and detach from the build plate. When plastics are printed, they firstly expand slightly but contract as they cool down. If material contracts too much, this causes the print to bend up from the build plate. Some materials shrink more than others (e.g. PC has a higher shrinkage than PLA), which means there’s a larger chance of warping when using it.

On this page, we will explain how to avoid or minimize print warping.

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Adhesion to the build plate

To prevent warping, you need to ensure that the 3D print adheres well to the build plate. Without good adhesion, your print can become loose. This is particularly common at the corners. There are several ways to improve build plate adhesion, which are explained here.

Use a heated build plate

The best way to avoid warping is by using a heated build plate. This keeps the material at a temperature just below the point where it solidifies (the glass transition temperature), ensuring it stays flat and connected to the build plate. When you use a heated build plate it is important to use the right temperature. To find the right temperature for your material, please refer to our material guides.

Ensure the build plate is leveled correctly

It is important that the first print layer of a print is pressed firmly onto the glass plate, to allow it to bond properly. If the distance between the nozzle and build plate is too wide, the material can easily become loose. If you are experiencing problems with the first print layer, we recommend re-leveling your build plate. You can find out how to do this by reading the following guides:

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Apply an adhesive

To ensure that the print adheres well it is important that the print surface is smooth and clean. There should be no traces of oil or grease on it, as this will worsen the adhesion. When using a heated build plate, it’s recommended that you apply an adhesive to the glass plate. Adhesion methods differ per material – please refer to the material manuals for further information.

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Applying glue to the glass plate can help improving the adhesion

Use a brim

Cura has a built-in feature called a ‘brim,’ which is an effective way to stop your print from warping. This places a single-layer-thick, flat area around your object, which resists the pulling forces as the print cools. As the brim is only a single layer thick, it’s easy to remove once the print’s finished. Refer to the Cura manual for further information.

Use a raft

For some materials or models, a brim might not be enough to prevent warping. In these instances, using a raft is advisable. A raft adds a thick grid between the model and the build plate, ensuring that the heat is distributed equally. It is particularly useful when the bottom of a model is not completely flat, or when printing with industrial materials. For more information about raft settings refer to the Cura manual.

Adjust the initial layer settings

Two important settings (relating to the first layer) that influence adhesion are the initial layer height and initial layer speed. In most cases, a thicker initial layer makes adhesion easier, as build plate calibration is not as critical. It is important not to set the initial layer speed too high, as the material may attach to the nozzle and get dragged around with it, instead of remaining fixed to the build plate.

Cooling

Cooling is one of the main causes of warping. Material contracts when cooling, and can cause the material to pull on itself. Materials need to be cooled properly before the next layer is added, but excessive cooling should be avoided to ensure a smooth, warp-free print.

Use the fan settings properly

The print head fans are usually turned off (fan speed = 0) for the first print layer, to ensure optimum build plate adhesion. Cura offers a range of fan settings to help avoid warping, such as ‘regular fan speed at height’ and ‘number of slower layers’. ‘Regular fan speed at height’ defines the height at which the fans will turn on, and ‘the number of slower layers’ sets the fan speed to increase gradually over a set amount of layers. To prevent warping, it’s advisable to leave the fans off for the first layer or to slowly increase the fan speed during the first few layers. This ensures that the bottom layer of the print maintains its temperature and avoids excessive cooling.

Print with a draft shield

Cura offers the (experimental) option to print with a draft shield. This creates a one-layer thick wall around your model, preventing unwanted airflows from cooling it excessively.

Using a draft shield to prevent unwanted airflows

Use a front-side door

Placing an enclosure around the model also protects it from airflow. Warmth is kept inside the printer, resulting in a more stable printing environment. When printing with industrial materials (e.g. PC and CPE+) an enclosure is strongly advised due to the high printing temperatures required. For more information about using a door, please refer to the Advanced 3D Printing Kit or material guides.

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